Liquid Crystals - a brief introduction

There are 3 main liquid crystalline phases. These are listed below.

		Starting at high temperature, we find the isotropic (random) phase, which does not possess orientational or translational order.
		Cooling in temperature, we find the nematic phase, here the molecules are orientated in the same general direction. So they have orientational order, but no translational order as yet.
		Cooling further in temperature, we find the smectic phases, here the molecules are orientated in the same general direction and have ordered in one dimension, i.e. layered. So they have orientational and translational order. However, each layer is still fluid.
		Finally, we get to the crystalline phase, here we have long-ranged orientational and translation order.

In addition to the phases above the bent-core molecules can also form unusual smectic phases.

		In this diagram it can be seen that all the layer polarisations (yellow arrows) are pointing in the same direction, hence this is a Ferroelectric phase. It can also be seen from the right projection that all the layers are tilted in the same sense with respect to the layer polarisations As a result this phase is known as Chiral Ferroelectric .
		In this diagram it can be seen that all the layer polarisations (yellow arrows) are pointing in the same direction, hence this is a Ferroelectric phase. It can also be seen from the right projection that all the layers are not tilted in the same sense with respect to the layer polarisations. As a result this phase is known as Racemic Ferroelectric .
		In this diagram it can be seen that all the layer polarisations (yellow arrows) of adjecant layers are pointing in opposite directions, hence this is a Antiferroelectric phase. It can also be seen from the right projection that all the layers are tilted in the same sense with respect to the layer polarisations. As a result this phase is known as Chiral Antiferroelectric .
		In this diagram it can be seen that all the layer polarisations (yellow arrows) of adjecant layers are pointing in opposite directions, hence this is a Antiferroelectric phase. It can also be seen from the right projection that all the layers are nottilted in the same sense with respect to the layer polarisations. As a result this phase is known as Racemic Antiferroelectric.

It must be noted that the majority of real bent-core systems form racemic phases as opposed to chiral phases.